Musicians, artists, politicians, activists, park lovers, labor leaders and the indefatigable Reverend Billy with his Church of Stop Shopping Choir gathered last Thursday night to celebrate the 10th anniversary of Union Square’s dedication as a national historic landmark.

They also came to raise their voices yet again against the plan by the Union Square Partnership business improvement district and the Parks Department to put a seasonal, private restaurant in the park’s historic pavilion.

The 1998 designation noted the park’s hosting of the first Labor Day parade in 1882, which led to creation of the Labor Day holiday. Over the decades, the park has hosted pro-labor parades, antiwar rallies and the four-days-a-week Greenmarket.

A pair of local elected officials, Assemblymembers Richard Gottfried and Deborah Glick, participated in last Thursday’s event.

“I’m here to oppose the pavilion restaurant plan and speak out for restoring the pavilion to use by the community,” Gottfried said as people gathered in the square’s south end. “We do need more space for free speech, activities for kids and all the other things people do in a park.”

Passersby were invited to join the draw-a-thon, an opportunity to portray how they would imagine the pavilion in the future as an integral part of public space.

“The privatization of public space is infringing on all space in New York,” Dashow said while sketching floating structures.

Reverend Billy’s hand was guided, perhaps by some divine inspiration, to draw several blooming trees.

“I’m bringing back the 90-year-old elm trees that were slaughtered,” Billy said while filling a large white sheet with green swirls. “We like to think about our teachers, our heroes — the Emma Goldmans, the Paul Robesons — when these elm trees were younger.”

Former Assemblymember Sylvia Friedman, now chairperson of the Union Square Community Coalition, was less poetic.

“What’s going on is a disgrace. This square is surrounded by restaurants. We don’t need another one,” she said.

A community lawsuit has stopped construction of a restaurant in, but not renovation of, the pavilion. The lawsuit will continue in court next month.

Former Village Councilmember Carol Greitzer held a sign reading, “Restore the Children’s Pavilion!!! Stop the BID.”

“The pavilion should not have a restaurant in it,” Greitzer said. “It should have an extension of the playground as part of a sheltered recreation area.”

The park’s historic landmark designation was due to the efforts of labor historian Debra Bernhardt. Bernhardt, who died in 2001, was represented at Thursday’s celebration by her husband, Jonathan Bloom, and their daughter, Sonia.

An eclectic list of speakers recalled the park’s glory and detailed their hopes for a future free of privatization.

“This park, probably more than any other park in the city, is defined by the people who use it,” said Ed Ott, executive director of the New York City Central Labor Council. Looking toward Fourth Ave., he recalled, “When Klein’s was still across the east side of the park, I can remember people getting up on soapboxes to debate.”

“Has anyone fallen in love here in Union Square with a total stranger?” asked Reverend Michael Ellick, assistant minister of Judson Memorial Church. His question brought cheers, laughter and his own reply, “I do more than I care to admit,” he said, adding, “We have the sacred responsibility to hold on to our public spaces.”

Said Glick, “Our public spaces are being privatized and taken away from the people. We have to continue to fight for open space for the public.” She criticized the city’s allegiances with private enterprise, deploring the city for having money for the Yankees new stadium but not for parks.